Copyright 2007 TeX Users Group.
You may freely use, modify and/or distribute this file.

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		CHANGED.EXE (file: changed.txt)  revised 1994/July/1
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A new PostScript file processing utility is provided with DVIPSONE 
that has two uses: 

*	Extracting pages that have changed with respect to a previous version;

*	Extracting specified page ranges and reordering pages in a PS file;

The utility is designed for use on output from DVIPSONE, but can also be used
on PS files produced by programs other than DVIPSONE.  However it assumes that

	(i)  the PS file is DSC (Document Structuring Convention) compliant,
	(ii) the PS file is page independent;

(i.e. no font definitions in the middle of the file).  Unfortunately quite
a few applications to not produce clean PostScript files that satisfy both of 
these requirements (such as most all Macintosh and Windows applications).

PRINTING ONLY PAGES THAT HAVE CHANGED:
--------------------------------------

The utility `changed' can compare two PS files and copy the pages with
differences to the output file, called `changed.ps', which is deposited in
the current directory.  For this to be useful, you need to keep the PS files
produced by DVIPSONE, and use the same command line flags in the two runs of
DVIPSONE.  The command line invocation is:

	changed [-v] <old-PS-File> <new-PS-File>

In this mode of usage, the utility `changed' takes two command line
arguments, the `old' PS file and the `new' PS file.  The two files are not
treated exactly symmetrically.  The header in the output file is copied from
the `new' PS file.  The header in the old PS file is ignored.  Pages that
appear in the new file, but do not appear in the old file are copied to the
output.  Pages that appear in the old file, but do not appear in the new file
are ignored.

EXTRACTING PAGES, REORDERING PAGES:
-----------------------------------

The utility `changed' can also be used to extract specified page ranges 
from a DSC compliant PostScript file.  The pages are specified by a comma
separated page range list.  For example:

	changed  -v  -P=3-7,43-39,5,63  myfile.ps

A page range of just one page is indicated by a single number (e.g. 5 above).
`Inverted' page ranges (e.g. 43-39) yield pages in reverse order.  
A particular page may appear more than once (e.g. page 5 above).

The page numbers are physical (sequential) pages within the file (using the
second number in %%Page: ... comment).  Use -p instead or -P to instead use
the logical page numbers (using the first number in %%Page: ... comment).  
As usual, there are potential problems if logical page numbers are repeated 
in the source file.  In this case `changed' picks the first page with a given
page number.

Pages are output in the order specified in the page range list.
Use the command line argument `r' to instead output pages in the order 
that they appear in the source file.

You can use other delimiters, such as + or :, instead of comma.  
This is convenient when invoking `changed' using a batch file, 
since commas break up the list into separate batch file arguments.